Improvement in screw-propellers



I k, 'di' WILLIAM S. HULL, or IIINDS COUNTY, MISSISSIPPI.

, IMPROVEMENT In scnEwfPRoPELLERs.

Specilication' forming part of Letters Patent N o. 187,633-,` datedFebruary 20,1871; application filed November 7, 1876.`

To all whom it may concern :v

Be it known that I, WILLIAM S. HULL, of the county of Hinds and State ofMississippi, have invented a new and Improved Propeller; and I do herebydeclare that the following .is a full, clear, and exact description ofthe same,

' reference being had to the accompanying drawing, forming part of thisspecication, in which.-

Figure 1 is a Vside View, and Fig. 2 an end view.

My invention relates to a novel construction of propeller, designed tosecure a greater driving capacity with a smaller Aexpenditure I ofpower, and adapted to operate either upon the air or water as a fulcrum.

The invention consists in a set of rightangled triangular vanes, blades,or fans, one side of each of which blades is attached to thepropeller-shaft at right angles thereto,

while the rear and less acute apices are deflected away from the saidshaft, the laterally projecting tapering blades thus constructed andarranged serving to distribute the work in ratio corresponding to theleverage throughout the length of the blades, and

thus securing a greater motive effect from a smaller expenditure ofpower.

In the accompanying drawing, A represents a portion of thepropeller-shaft, to which the4 blades are attached, which shaft is to belocated in bearings, and rotated by connection with any suitable drivingmechanism. B B B are the right-angled triangular blades,

which are attached at their right angles to light material, attached attheir front sides' to stiff laterally-projecting radial arms D D D, andat their rear deflected apices to corresponding radial arms G G C, or,when used to operate upon water as a fulcrum, may be cast in one piece,stiff enough to dispense with said arms C and D, and provided with acoupling at their right angles for direct atlengthiof the larger side atright angles to the shaft.

The blades I find, however, work well for a variation of fifteen degreesupon either side of the angle thus formed, and I therefore do Inot limitmyself in this particular. The face of the@ blades which operates uponthe fluid shouldbe straight, or nearly so, in order to reduce as far aspossible the friction incident to the `curves of propellers, asheretofore constructed, and any number of blades may be employed in theconstruction of the propeller Propellers as heretofore constructed havegenerally their widest faces and largest propelling-surfaces at theextremity or long end ot' the lever, the effect of which is seen in thegreat expenditure of power required to propel, a large portion of whichpower expended is lost in carrying dead-water.

By means of the propeller blades constructed as described, it will beseen that the resisting surface is distributed throughout the length ofthe blade in proper ratio to the leverage; and I am thus enabled tosecure the maximum effect of the propelling power with the smallestamount lof resistance.

By the Same construction of blade, also, when arranged as described, Iam enabled'to employ the full width of the blade near the shaft, withoutthe cbjection of a lack Vof clearance for the fluid operated upon, theldeflection of,` the rear apex of the bladefrom the shaft permitting afree and easy passage of the iiuid to the rear.

Having thus described my invention, what I claim as newisrIheeornbination, with the propeller-shaft, of a series ofright-angled triangular blades, having their front sides attached tosaid shaft at right angles, and their rear apices deiiected away fromthesame, substantially as and for the purpose described.

i WILLIAM S.. HULL.

Witnesses:

`W. S. HAMILTON, JNO. T. HALL.

